Weighing in at 52 pages this PDF presents us with a core bestiary for the Shadowsfall setting, and one seriously twisted collection of critters. The page breakdown is as follows:
Covers, Front & Back: 1 page each
Blank pages: 2, 1 after front cover, and 1 before back cover
SRD, TOC: 1 page each
List of suitable monsters from other sources: 1 page, and an interesting idea to support core products in a very useful manner. Extremely helpful list for a GM.
Advertisement: 1 page, showcasing the Player's companion and Gazetteer for Shadowsfall
New Material: 30 pages of new or variant monsters
Appendices: 14 pages of variants, CR listings, universal rules, new feats, etc.
Formatting follows the standard dual column look for monster statblocks we've all come to know, with embedded artwork that ranges from really spectacular to OK. All interior artwork is B&W, with a few pieces of stock art that prove perhaps the stock pool needs to be replenished (I've seen a few of these pieces elsewhere, several times). Grammatically there were a few missteps, but nothing that couldn't be worked out for meaning quickly enough (i.e. Black work poison instead of Black worm poison or a racid stench for a rancid stench).
Now, before I go into detailing any of the creatures within this collection, I want to point out one of the cooler features of this book in my opinion. The creatures are presented with advice, words of wisdom if you will, from others who have encountered them. The inclusion of this really helps sell the immersion factor, and added a very cool factor to this book making it more than just another collection of monsters. There are also many, many references to pieces of literature detailing these creatures within the Shadowsfall setting, which I love, because it's another immersion technique, and a great way to introduce tomes to our players.
So, let's take a look at the beasties, shall we?
Black Worm: A colossal beast, think the shadow planes answer to the purple worm...on steroids....pissed. At a CR18 this monstrosity can swallow you, that town, and the hamlet on the other side of the river..whole....It's fricking huge, and has a breath weapon to boot. One seriously wicked worm folks.
Centaur Raav: A skeletal abomination built from the bones of a centaur and armed with bone spikes and blades protruding from its extremities, this is one seriously wicked looking creature.
Clawed Kadian: An interesting take on a ghost, the creature is a ghost who is still corporeal, with incorporeal attack options.
Darkling: Now this, this is how dark fey should be presented. The darkling actually accelerates its healing by licking the blood of its victims from its axe or claws....that's just so twisted. Well done.
Deathhand: The ferryman's personal hunting dogs, a deathhand would be the last thing you ever want to stumble across. Charged with collecting those who have tasted death, these are seriously dangerous opponents to have to face in combat. Also presented within this entry are several Deathhand Captains, while no stats are presented, more than enough adventure hooks and thoughts on their advanced nature is provided to use them easily enough.
Quake Dragon With how often we see a variant dragon show up in a new creature book, it is always a pleasure to find one that really is good, and manages to feel fresh and new without departing from the concept of what a dragon is. The quake dragon is presented with a full age progression chart, as well as a couple of full statblocks for various points in it's lifespan. A well thought out creature, with some interesting abilities, like Earth Glide – allowing it to essentially swim through earth, leaving no tunnel or trace of its passing.
Dread Gargoyle: A larger, more dangerous variety of the standard gargoyle with the ability to manipulate its own body to always have stones ready to throw.
Dull Mite: The shadowplane variant on the material plane's Mite, these little fey have been drained of their color, and have the ability to steal their targets, resulting in Charisma penalties.
Shadow Elemental: Detailing a standard as well as a range from small through huge, greater and elder, this entry gives you a total of 6 variations of this elemental.
Great Dodo: Gargantuan in size and pissed that your grandpa ate its cousins, this giant bird has a score to settle.
Headless Hunchback Skeleton: Both a standard and a champion variety are presented.
Helblar: 3 full statblocks for a standard, greater and champion are presented for this odd guardian of the dead and their resting places.
Kyton, Dermistide: Wrapped in bandages that it can control to grapple and flay its targets with, this particular kyton variant is twisted in it's sadism.
Kyton, Noxil: Only as large as a halfling, these wretches have their heads encased in a spiked harness whilst a pendulum blade hangs suspended from their necks.
Monkeybat: So, channeling their inner Oz, this creature not only satisfies those looking for winged monkeys, but goes that extra mile and gives us the adventure hook of the entire arrival of Dorothy (now renamed Dorhana Breeze). Liked the creature, would have liked it more without the over the top references to Baum's characters. It was strong enough to stand on its own, it really was.
Nightshade, Nightstalker: A commander of skeletal armies, this undead lion of shadow hunts the negative plane for the living.
Onyx Ooze: killing with a “cold acid”, the Onyx Ooze is a far more cunning predator than your standard ooze.
Phantasm Swarm: A collection of souls denied an eternal reward after death, this collective rages against religion, and those that serve it.
Psychopomp, Memitim: A collector of souls essentially, the memitim's purpose is to make sure that powerful souls pass on, and do not end up as undead.
Shade Anuran: A frog like race with an interesting ability to utilize the shadows around them.
Spectres: Stats presented for both a spawn and a lord, as are enough fluff to work two epic spectres into a campaign.
Spiderbear: Remember that spider you squished in the shower? Pray these never find out. All the abilities and poison of a giant spider merged with the power, strength and claws of a bear.....dear lord forgive us our spider squishing, we know not what we might be pissing off.
Starak: The ShadowPlane's answer to the Tarrasque, a colossal beast that sleeps for centuries, eats and demolishes nations, and is pretty much an all around bad ass. Add to that a deafening roar, and you have yourself a contender for that massave monster fight you've always wanted to stage (tarrasque vs. starak anyone?)
Unquiet Giant: Ok, I love me some undead, I do. But this feels like a template, not a monster. It's cool, it is, but in presenting it in this manner I am left wondering, if this is an undead giant, what race of giant was it before it died? What happened to those abilities it had in life?
Vampiric Tree: darting its targets with poison sap covered bark, this tree then “bites” into its prey with it's roots, draining them of their blood.
Appendix 1: Shadows - statblocks for variant shadows, who ever said shadows are only human?
]Appendix 2: Skeletons- variant skeletons, including the monkey and minotaur skeletons
Appendix 3: Zombies- variant zombies including a bulette, a basilisk and a gnome.
Appendix 4: Darkened Template- template to transform any creature into a being embraced by the realm of shadow. Example creatures include the Darkened Giant Centipede and Darkened Kraken.
Appendix 5: Universal Monster Rules- 4 pages detailing the universal abilities found within statblocks, helping to keep the statblocks more streamlined and clean looking by organizing all of this information together.
Appendix 6: Feats 1 ½ pages detailing the new feats scattered through statblocks throughout this PDF. Appendix 7: New Creature Subtypes- small paragraph covering the Shadow subtype.
Appendix 8: Creatures by CR- ½ page list

All in all, a fantastic collection of creatures. There are a few that did not grab me, and this is normal in a collection of this nature, as the standard right off the bat was set pretty high with the Black Worm, raising the stakes for all creatures after it. As a sourcebook for the Shadowsfall setting, this book is a must, but even without using this specific setting, this collection of creatures is a treasure trove of diabolical deliciousness. Giving this book a solid 5 stars rating, and highly recommending it to any and all GM's out there.